U.S. patent application number 12/951938 was filed with the patent office on 2012-05-24 for uplink data arrival random access procedure.
This patent application is currently assigned to QUALCOMM INCORPORATED. Invention is credited to Mouaffac Ambriss, Girish Khandelwal, Shailesh Maheshwari, Bao Vinh Nguyen.
Application Number | 20120127930 12/951938 |
Document ID | / |
Family ID | 45316070 |
Filed Date | 2012-05-24 |
United States Patent
Application |
20120127930 |
Kind Code |
A1 |
Nguyen; Bao Vinh ; et
al. |
May 24, 2012 |
UPLINK DATA ARRIVAL RANDOM ACCESS PROCEDURE
Abstract
User equipment (UE) transmits an access response to a random
access procedure (RACH) preamble message to acquire an uplink grant
from a node of a wireless communication system. The access response
provides an uplink grant to the UE for a request for authorization
to transmit uplink data to the node. In response to determining
that the access response message provides an uplink grant
sufficient to empty the UE's data buffer, the UE transmits the
request for authorization including the uplink data to the node.
The UE can then terminate the RACH procedure without requiring any
subsequent uplink grant from the node, having accomplished
successful data transmission using the request for
authorization.
Inventors: |
Nguyen; Bao Vinh; (Corona,
CA) ; Maheshwari; Shailesh; (San Diego, CA) ;
Khandelwal; Girish; (San Diego, CA) ; Ambriss;
Mouaffac; (San Diego, CA) |
Assignee: |
QUALCOMM INCORPORATED
San Diego
CA
|
Family ID: |
45316070 |
Appl. No.: |
12/951938 |
Filed: |
November 22, 2010 |
Current U.S.
Class: |
370/329 |
Current CPC
Class: |
H04W 72/1284 20130101;
H04W 74/0866 20130101; H04W 74/002 20130101 |
Class at
Publication: |
370/329 |
International
Class: |
H04W 12/06 20090101
H04W012/06 |
Claims
1. A method, comprising: receiving, an access response to a random
access channel (RACH) procedure preamble message to acquire an
uplink grant from a node of a wireless communication system,
wherein the access response provides an uplink grant to a user
equipment (UE) for a request for authorization to transmit uplink
data to the node; and transmitting the request for authorization
including the uplink data to the node in response to determining
that the access response message provides an uplink grant
sufficient to empty the UE's data buffer, thereby enabling
termination of the RACH procedure without requiring any subsequent
uplink grant from the node.
2. The method of claim 1, further comprising providing an
indication that the UE's data buffer is empty in the request for
authorization.
3. The method of claim 2, wherein providing the indication is
performed by using a Buffer Status Report (BSR) data signal.
4. The method of claim 1, further comprising initializing a
contention resolution timer in response to transmitting the request
for authorization.
5. The method of claim 4, further comprising including a Cell Radio
Network Temporary ID (C-RNTI) Media Access Control (MAC) control
element in the request for authorization.
6. The method of claim 5, further comprising stopping the
contention resolution timer and discarding a temporary C-RNTI, in
response to receiving a Physical Downlink Control Channel (PDCCH)
transmission addressed to the C-RNTI after transmitting the request
for authorization.
7. The method of claim 5, further comprising including a Common
Control Channel (CCCH) Service Data Unit (SDU) in the request for
authorization.
8. The method of claim 7, further comprising stopping the
contention resolution timer and discarding a temporary C-RNTI, in
response to determining that a UE Contention Resolution Identity
decoded from a MAC Protocol Data Unit (PDU) matches the CCCH
SDU.
9. The method of claim 8, further comprising disassembling and
demultiplexing the MAC PDU, further in response to determining that
a UE Contention Resolution Identity decoded from a MAC Protocol
Data Unit (PDU) matches the CCCH SDU.
10. The method of claim 5, further comprising discarding a
temporary C-RNTI in response to expiration of the contention
resolution timer.
11. The method of claim 10, further comprising reinitiating the
RACH procedure for uplink of data after waiting for a backoff
period.
12. A computer program product, comprising: a computer-readable
storage medium comprising code for causing a computer to: receive,
an access response to a random access channel (RACH) procedure
preamble message to acquire an uplink grant from a node of a
wireless communication system, wherein the access response provides
an uplink grant to a user equipment (UE) of a request for
authorization to transmit uplink data to the node; and transmit the
request for authorization including the uplink data to the node in
response to determining that the access response message provides
an uplink grant sufficient to empty the UE's data buffer, thereby
enabling termination of the RACH procedure without requiring any
subsequent uplink grant from the node.
13. The computer program product of claim 12, wherein the
computer-readable storage medium further comprises code for causing
a computer to provide an indication that the UE's data buffer is
empty in the request for authorization.
14. The computer program product of claim 12, wherein the
computer-readable storage medium further comprises code for causing
a computer to provide the indication using a Buffer Status Report
(BSR) data signal.
15. The computer program product of claim 12, wherein the
computer-readable storage medium further comprises code for causing
a computer to initialize a contention resolution timer in response
to transmitting the request for authorization.
16. The computer program product of claim 15, wherein the
computer-readable storage medium further comprises code for causing
a computer to include a Cell Radio Network Temporary ID (C-RNTI)
Media Access Control (MAC) control element in the request for
authorization.
17. The computer program product of claim 16, wherein the
computer-readable storage medium further comprises code causing a
computer to stop the contention resolution timer the C-RNTI, in
response to receiving a Physical Downlink Control Channel (PDCCH)
transmission addressed to the C-RNTI after transmitting the request
for authorization.
18. The computer program product of claim 15, wherein the
computer-readable storage medium further comprises code for causing
a computer to include a Common Control Channel (CCCH) Service Data
Unit (SDU) in the request for authorization.
19. The computer program product of claim 18, wherein the
computer-readable storage medium further comprises code for causing
a computer to stop the contention resolution timer and discard a
temporary C-RNTI, in response to determining that a UE Contention
Resolution Identity decoded from a Protocol Data Unit (PDU) matches
the CCCH SDU.
20. The computer program product of claim 19, wherein the
computer-readable storage medium further comprises code for causing
a computer to disassemble and demultiplex the MAC PDU, further in
response to determining that a UE Contention Resolution Identity
decoded from a MAC Protocol Data Unit (PDU) matches the CCCH
SDU.
21. The computer program product of claim 16, wherein the
computer-readable storage medium further comprises code for causing
a computer to discard a temporary C-RNTI in response to expiration
of the contention resolution timer.
22. The computer program product of claim 21, wherein the
computer-readable storage medium further comprises code for causing
a computer to reinitiate the RACH procedure for uplink of data
after waiting for a backoff period.
23. An apparatus, comprising: means for receiving, an access
response to a random access channel (RACH) procedure preamble
message to acquire an uplink grant from a node of a wireless
communication system, wherein the access response provides an
uplink grant to a user equipment (UE) for a request for
authorization to transmit uplink data to the node; coupled to means
for transmitting the request for authorization including the uplink
data to the node in response to determining that the access
response message provides an uplink grant sufficient to empty the
UE's data buffer, thereby enabling termination of the RACH
procedure without requiring any subsequent uplink grant from the
node.
24. The apparatus of claim 23, further comprising means for
providing an indication that the UE's data buffer is empty in the
request for authorization.
25. The apparatus of claim 23, further comprising means for
providing the indication using a Buffer Status Report (BSR) data
signal.
26. The apparatus of claim 23, further comprising means for
initializing a contention resolution timer in response to
transmitting the request for authorization.
27. The apparatus of claim 26, further comprising means for
including a Cell Radio Network Temporary ID (C-RNTI) Media Access
Control (MAC) control element in the request for authorization.
28. The apparatus of claim 26, further comprising means for
stopping the contention resolution timer the C-RNTI, in response to
receiving a Physical Downlink Control Channel (PDCCH) transmission
addressed to the C-RNTI after transmitting the request for
authorization.
29. The apparatus of claim 26, further comprising means for
including a Common Control Channel (CCCH) Service Data Unit (SDU)
in the request for authorization.
30. The apparatus of claim 29, further comprising means for
stopping the contention resolution timer and discarding a temporary
C-RNTI, in response to determining that a UE Contention Resolution
Identity decoded from a Protocol Data Unit (PDU) matches the CCCH
SDU.
31. The apparatus of claim 30, further comprising means for
disassembling and demultiplexing the MAC PDU, further in response
to determining that a UE Contention Resolution Identity decoded
from a MAC Protocol Data Unit (PDU) matches the CCCH SDU.
32. The apparatus of claim 27, further comprising means for
discarding a temporary C-RNTI in response to expiration of the
contention resolution timer.
33. The apparatus of claim 32, further comprising means for
reinitiating the RACH procedure for uplink of data after waiting
for a backoff period.
34. A wireless communication apparatus comprising: a memory holding
instructions for receiving, an access response to a random access
channel (RACH) procedure preamble message to acquire an uplink
grant from a node of a wireless communication system, wherein the
access response provides an uplink grant to a user equipment (UE)
for a request for authorization to transmit uplink data to the
node, and, transmitting the request for authorization including the
uplink data to the node in response to determining that the access
response message provides an uplink grant sufficient to empty the
UE's data buffer, thereby enabling termination of the RACH
procedure without requiring any subsequent uplink grant from the
node; and a processor that executes the instructions.
35. The apparatus of claim 34, wherein the memory holds further
instructions for providing an indication that the UE's data buffer
is empty in the request for authorization.
36. The apparatus of claim 34, wherein the memory holds further
instructions for providing the indication using a Buffer Status
Report (BSR) data signal.
37. The apparatus of claim 34, wherein the memory holds further
instructions for initializing a contention resolution timer in
response to transmitting the request for authorization.
38. The apparatus of claim 37, wherein the memory holds further
instructions for including a Cell Radio Network Temporary ID
(C-RNTI) Media Access Control (MAC) control element in the request
for authorization.
39. The apparatus of claim 38, wherein the memory holds further
instructions for stopping the contention resolution timer the
C-RNTI, in response to receiving a Physical Downlink Control
Channel (PDCCH) transmission addressed to the C-RNTI after
transmitting the request for authorization.
40. The apparatus of claim 38, wherein the memory holds further
instructions for including a Common Control Channel (CCCH) Service
Data Unit (SDU) in the request for authorization.
41. The apparatus of claim 40, wherein the memory holds further
instructions for stopping the contention resolution timer and
discarding a temporary C-RNTI, in response to determining that a UE
Contention Resolution Identity decoded from a Protocol Data Unit
(PDU) matches the CCCH SDU.
42. The apparatus of claim 41, wherein the memory holds further
instructions for disassembling and demultiplexing the MAC PDU,
further in response to determining that a UE Contention Resolution
Identity decoded from a MAC Protocol Data Unit (PDU) matches the
CCCH SDU.
43. The apparatus of claim 38, wherein the memory holds further
instructions for discarding a temporary C-RNTI in response to
expiration of the contention resolution timer.
44. The apparatus of claim 42, wherein the memory holds further
instructions for reinitiating the RACH procedure for uplink of data
after waiting for a backoff period.
Description
BACKGROUND
[0001] I. Field
[0002] The following description relates generally to wireless
communications systems, and more particularly to uplink data
arrival in a wireless communications network.
[0003] II. Background
[0004] Wireless communication systems are widely deployed to
provide various types of communication content such as voice, data,
and so forth. These systems may be multiple-access systems capable
of supporting communication with multiple users by sharing the
available system resources (e.g., bandwidth and transmit power).
Examples of such multiple-access systems include code division
multiple access (CDMA) systems, time division multiple access
(TDMA) systems, frequency division multiple access (FDMA) systems,
3GPP Long Term Evolution (LTE) systems including Evolved UTRA
(E-UTRA), and orthogonal frequency division multiple access (OFDMA)
systems. Each of the foregoing systems operates over licensed
frequency spectrums, and licensee operators generally provide
access to users according to a subscription model. The technology
described herein pertains to these and similar systems.
[0005] An orthogonal frequency division multiplex (OFDM)
communication system effectively partitions the overall system
bandwidth into multiple (N.sub.F) subcarriers, which may also be
referred to as frequency sub-channels, tones, or frequency bins.
For an OFDM system, the data to be transmitted (i.e., the
information bits) is first encoded with a particular coding scheme
to generate coded bits, and the coded bits are further grouped into
multi-bit symbols that are then mapped to modulation symbols. Each
modulation symbol corresponds to a point in a signal constellation
defined by a particular modulation scheme (e.g., M-ary Phase-Shift
Keying (M-PSK) or Multi-Level Quadrature Amplitude Modulation
(M-QAM)) used for data transmission. At each time interval that may
be dependent on the bandwidth of each frequency subcarrier, a
modulation symbol may be transmitted on each of the N.sub.F
frequency subcarrier. Thus, OFDM may be used to combat inter-symbol
interference (ISI) caused by frequency selective fading, which is
characterized by different amounts of attenuation across the system
bandwidth.
[0006] Generally, a wireless multiple-access communication system
can concurrently support communication for multiple wireless
terminals such as mobile stations, also called user equipment (UE),
that communicate with one or more base stations via transmissions
on forward and reverse links. The downlink (or forward link) refers
to the communication link from the base stations to the mobile
stations, and the reverse link (or uplink) refers to the
communication link from the mobile stations to the base stations.
This communication link may be established via a
single-in-single-out, multiple-in-signal-out or a
multiple-in-multiple-out (MIMO) system.
[0007] A MIMO system employs multiple (N.sub.T) transmit antennas
and multiple (NR) receive antennas for data transmission. A MIMO
channel formed by the N.sub.T transmit and N.sub.R receive antennas
may be decomposed into N.sub.S independent channels, which are also
referred to as spatial channels. Generally, each of the N.sub.S
independent channels corresponds to a dimension. The MIMO system
can provide improved performance (e.g., higher throughput and/or
greater reliability) if the additional dimensionalities created by
the multiple transmit and receive antennas are utilized. A MIMO
system also supports time division duplex (TDD) and frequency
division duplex (FDD) systems.
[0008] Uplink data arrival protocols govern uplink of data from the
UE to the base station in many wireless communication systems, and
different protocols may apply to different circumstances within the
same system. For example, the Evolved Universal Terrestrial Radio
Access (E-UTRA) Medium Access Control (MAC) protocol specification
specifies that an Uplink Data Arrival (ULDAR) Random Access Channel
(RACH) procedure is performed for uplink of data under certain
conditions. Use of the RACH procedure or similar methods requiring
contention resolution may sometimes result in less than optimal
efficiency in data transfer. A new or modified implementation of a
RACH procedure would therefore be desirable, to overcome these and
other limitations of random access channel procedures requiring
contention resolution.
SUMMARY
[0009] The following presents a simplified summary in order to
provide a basic understanding of some aspects of the claimed
subject matter. This summary is not an extensive overview, and is
not intended to identify key/critical elements or to delineate the
scope of the claimed subject matter. Its sole purpose is to present
some concepts in a simplified form as a prelude to the more
detailed description that is presented later.
[0010] In accordance with one or more embodiments and corresponding
disclosure thereof, various aspects are described in connection
with methods for femtocell access control. The methods may be
performed in a wireless communication network comprising at least
one base station or node configured for wireless communication with
user equipment (UE) accessing the network via the base station or
node. The wireless communication network may be any one of the
group consisting of a Session Initiation Protocol (SIP) based
circuit-switched network, an Interoperability Specification (IOS)
based circuit-switched network, and a packet-switched network
[0011] The methods may include receiving, an access response to a
random access channel (RACH) procedure preamble message to acquire
an uplink grant from a node of a wireless communication system. The
RACH procedure may be as specified by a 3GPP Long Term Evolution
(LTE) protocol, or may be a similar procedure as used in another
wireless communication protocol. The access response provides an
uplink data grant to at user equipment (UE) for a request for
authorization to transmit uplink data to the node. The access
response may also include a Temporary Cell Radio Network Temporary
ID (temporary C-RNTI or T-RNTI), which is a form of Cell Radio
Network Temporary ID (C-RNTI) Media Access Control (MAC) control
element used during the RACH procedure and discarded afterwards.
The methods may further include transmitting the request for
authorization including the uplink data to the node, in response to
determining that the access response message provides an uplink
data grant sufficient to empty the UE's data buffer. Including the
uplink data in the request for authorization enables termination of
the RACH procedure without requiring any subsequent uplink data
grant from the node. Thus, contention resolution is resolved more
efficiently and efficiency of communication is improved.
[0012] The methods may further include the UE providing an
indication that the UE's data buffer is empty, in the request for
authorization. The UE may perform providing the indication using a
Buffer Status Report (BSR) data signal. The methods may further
include initializing a contention resolution timer in response to
transmitting the request for authorization.
[0013] In addition, or in the alternative, the UE may include the
T-RNTI in the request for authorization. The methods may further
comprise the UE stopping the contention resolution timer and
discarding the T-RNTI, in response to receiving a Physical Downlink
Control Channel (PDCCH) transmission addressed to the T-RNTI after
transmitting the request for authorization.
[0014] In addition, or in the alternative, the UE may include a
Common Control Channel (CCCH) Service Data Unit (SDU) in the
request for authorization. The methods may further comprise the UE
stopping the contention resolution timer and discarding the T-RNTI,
in response to determining that a UE Contention Resolution Identity
decoded from a MAC Protocol Data Unit (PDU) matches the CCCH SDU.
The methods may further comprise the UE disassembling and
demultiplexing the MAC PDU, further in response to determining that
a UE Contention Resolution Identity decoded from a MAC Protocol
Data Unit (PDU) matches the CCCH SDU.
[0015] The methods may further comprise the UE discarding the
T-RNTI in response to expiration of the contention resolution
timer. The methods may further comprise the UE reinitiating the
RACH procedure for uplink of data after waiting for a backoff
period.
[0016] The technology may also be embodied in a communications
apparatus; for example, in user equipment implementing a wireless
communication protocol. That apparatus includes a memory that
retains instructions for performing any of the methods summarized
above, and a processor that executes the instructions. For example,
the instructions may provide for receiving an access response to a
RACH procedure preamble message to acquire an uplink grant from a
node of a wireless communication system. The instructions may
further provide that the access response provides a uplink data
grant to the UE for a request for authorization to transmit uplink
data to the node. The instructions may further provide transmitting
the request for authorization including the uplink data to the
node, in response to determining that the access response message
provides a uplink data grant sufficient to empty the UE's data
buffer. Including the uplink data in the request for authorization
enables termination of the RACH procedure without requiring any
subsequent uplink data grant from the node. Thus, the apparatus can
more efficiently resolve RACH contention resolution when the amount
of uplink data is small enough to be included in the RACH request
for authorization. The apparatus may therefore be used to improve
efficiency of communication in the wireless communication
network.
[0017] The technology may also be embodied in a computer program
product; for example, a computer-readable medium storing code for
causing a computer to perform any of the methods summarized above.
For example, the code may cause a UE to receive an access response
to a RACH procedure preamble message to acquire an uplink grant
from a node of a wireless communication system. The access response
may provide a uplink data grant to the UE for a request for
authorization to transmit uplink data to the node. The code may
further cause the computer to transmit the request for
authorization including the uplink data to the node, in response to
determining that the access response message provides a uplink data
grant sufficient to empty the UE's data buffer. By causing the UE
to include the uplink data in the request for authorization, the
computer program product enables termination of the RACH procedure
without requiring any subsequent uplink data grant from the node.
Thus, the computer program product can more efficiently resolve
RACH contention resolution when the amount of uplink data is small
enough to be included in the RACH request for authorization. The
computer program product may therefore be used to improve
efficiency of communication in the wireless communication
network.
[0018] In addition, a communications apparatus for performing the
methods may comprise means for performing any of the methods
described herein, such as either of the apparatus summarized above.
For example, an apparatus may comprise first means for receiving,
at user equipment implementing a wireless communication protocol,
an access response to a RACH procedure preamble message to acquire
an uplink grant from a node of a wireless communication system,
wherein the access response provides a uplink data grant to the UE
for a request for authorization to transmit uplink data to the
node. The apparatus may further comprise second means coupled to
the first means, the second means for transmitting the request for
authorization including the uplink data to the node in response to
determining that the access response message provides a uplink data
grant sufficient to empty the UE's data buffer, thereby enabling
termination of the RACH procedure without requiring any subsequent
uplink data grant from the node. Thus, the apparatus can more
efficiently resolve RACH contention resolution when the amount of
uplink data is small enough to be included in the RACH request for
authorization, and thereby improve efficiency of communication in
the wireless communication network.
[0019] To the accomplishment of the foregoing and related ends,
certain illustrative aspects are described herein in connection
with the following description and the annexed drawings. These
aspects are indicative, however, of but a few of the various ways
in which the principles of the claimed subject matter may be
employed and the claimed subject matter is intended to include all
such aspects and their equivalents. Other advantages and novel
features may become apparent from the following detailed
description when considered in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] Throughout the drawings and accompanying description, like
reference characters identify correspondingly like elements.
[0021] FIG. 1 is a flow diagram showing a method for an uplink data
arrival random access procedure.
[0022] FIG. 2 illustrates a multiple access wireless communication
system including a mobile station and a base station.
[0023] FIG. 3 illustrates an exemplary wireless communication
system.
[0024] FIG. 4 illustrates an exemplary communication system
including different types of access point base stations within a
network environment.
[0025] FIG. 5 is a block diagram showing examples of a base station
and user equipment as may be used to perform an ULDAR RACH
procedure as disclosed herein.
[0026] FIG. 6 is a sequence diagram showing an example of a
sequence for performing an ULDAR RACH procedure with uplink after
contention resolution.
[0027] FIG. 7 is a sequence diagram showing an example of a
sequence for performing an ULDAR RACH procedure with uplink prior
to contention resolution.
[0028] FIG. 8 is a block diagram showing an example of an apparatus
for performing an ULDAR RACH procedure.
[0029] FIG. 9 is a flow diagram showing additional actions that may
be performed in some embodiments of an ULDAR RACH procedure.
[0030] FIG. 10 is a block diagram showing an example of an
apparatus for performing the additional actions illustrated by FIG.
9.
[0031] FIG. 11 is a flow diagram showing additional actions that
may be performed in embodiments of an ULDAR RACH procedure in which
the UE transmits a temporary C-RNTI MAC control element to the base
station.
[0032] FIG. 12 is a block diagram showing an example of an
apparatus for performing the additional actions illustrated by FIG.
11.
[0033] FIG. 13 is a flow diagram showing additional actions that
may be performed in embodiments of an ULDAR RACH procedure in which
the UE transmits a CCCH SDU to the base station.
[0034] FIG. 14 is a block diagram showing an example of an
apparatus for performing the additional actions illustrated by FIG.
13.
[0035] FIG. 15 is a flow diagram showing relationships between
actions that may be performed by user equipment in different
embodiments of an ULDAR RACH procedure.
DETAILED DESCRIPTION
[0036] The Evolved Universal Terrestrial Radio Access (E-UTRA)
Medium Access Control (MAC) protocol specification (3GPP TS 36.321
V 8.5.0 Section 5.1) specifies that an Uplink Data Arrival (ULDAR)
Random Access Channel (RACH) procedure is performed for uplink of
data under certain conditions. These conditions may include, for
example, the UE detecting high data arrival while the uplink timing
is out of sync or the Scheduling Request (SR) resource is not
available. To successfully complete an ULDAR via a RACH, the RACH
procedure may be required to successfully pass contention
resolution. If contention resolution is not passed, the UE may
perform the RACH procedure continuously until the Radio Resource
Control (RRC) times out, alerting the UE to Radio Link Failure
(RLF). Therefore, systems, apparatus and methods are provided to
enable an ULDAR RACH procedure to accomplish data uplink without
requiring an uplink data grant from a RACH contention resolution
sequence, or in which RACH contention resolution is terminated
efficiently.
[0037] Aspects of a method 100 for performing an ULDAR RACH
procedure are shown in FIG. 1. A RACH procedure may be initiated by
a UE by transmitting a preamble message to a base station in a
wireless communication network. In LTE, the preamble message may be
referred to as "message 1," which may be abbreviated as "MSG1." A
preamble message is characterized by being an efficient wireless
signal indicating that the UE seeks to initiate a RACH procedure
for uplink of data, namely by requesting an uplink grant. The
preamble is designed to carry minimal information so as to conserve
system resources, and therefore does not include any information
about the data to be uplinked by the UE. In an aspect, the UE will
seek to initiate a RACH procedure for uplink of data in response to
detecting data arrival while either of the following conditions
apply: (1) uplink timing out of sync, or (2) the Scheduling Request
(SR) resource is not available.
[0038] In response to the preamble, the base station may transmit
an access response message to the UE. In LTE, the access response
message may be referred to as "message 2," which may be abbreviated
as "MSG2." An access response may be characterized by providing a
small uplink grant to the UE. The uplink grant may be large enough
to allow the UE to transmit a request for authorization to the base
station, and may vary depending on system parameters or may be
fixed depending on the applicable protocol. In an aspect, the
access response message may also transmit a temporary identifier to
the UE, such as, for example, a temporary C-RNTI. In a further
aspect, the access response message may transmit timing
instructions to the UE for a request for authorization.
[0039] Accordingly, method 100 may comprise the UE receiving 102 an
access response to a RACH preamble message to acquire an uplink
grant from a node (e.g., base station) of a wireless communication
system, wherein the access response provides an uplink grant to the
UE. In an aspect, the uplink grant received at step 102 is not for
the uplink data; i.e., is not for the arrived data detected by the
UE and stored in its buffer for uplink. Instead, the uplink grant
is for the UE to transmit a request for authorization to transmit
uplink data to the node (e.g., base station), because the preamble
does not provide the base station with any information about the
data to be uplinked, other than that the UE is seeking to uplink
data. For example, the preamble does not include information about
the amount of information to be uplinked. A purpose of the access
response is to provide the UE with a uplink grant, which the UE can
use to transmit information about the data to be uplinked in a
request for authorization, including the amount of data to be
uplinked.
[0040] In LTE, the RACH request for authorization may be referred
to as "message 3," which may be abbreviated as "MSG3." A request
for authorization may be characterized as being a scheduled
transmission as specified by the access response. In addition to
including data as specified herein, the access response may include
an identifier for the UE, for example, a C-RNTI and/or the
temporary C-RNTI, and a report indicating an amount of data in the
UE's uplink data buffer.
[0041] In response to the access response from the base station,
the UE may determine whether or not the uplink grant provided by
the access response is large enough to transmit the data to be
uplinked. In response to determining that the access response
message provides a uplink grant sufficient to empty the UE's data
buffer, the UE may transmit 104 the request for authorization to
the node, including the uplink data stored in its uplink data
buffer. The UE may also include a control signal in the request for
authorization, to indicate to the receiving node that the request
for authorization includes uplink data. For example, the UE may
include a signal indicating that its uplink data buffer is empty.
Transmitting the request for authorization including the uplink
data enables termination of the RACH procedure without requiring a
subsequent uplink data grant from the receiving node.
[0042] For example, if the request for authorization includes data
emptying the UE's uplink data buffer, and therefore includes a
buffer status report (BSR) indicating zero data remains to be
uplinked, the base station may, in response, transmit a contention
resolution message to the UE that does not include an uplink data
grant. In response to receiving such as contention resolution
message, the UE may terminate the RACH procedure. In LTE, the
contention resolution message may be referred to as "message 4,"
which may be abbreviated as "MSG4." The contention resolution
message may be characterized by resolving the RACH procedure, such
as by providing an uplink grant for the UE or by providing other
information enabling the UE to terminate the RACH procedure without
subsequent uplink of data. Thus, the UE accomplishes uplink of data
more efficiently, using fewer system resources. Further details and
various embodiments of method 100 in different contexts are
provided by the following detailed disclosure.
[0043] Having described an example of an ULDAR RACH at a relatively
high level of generality, examples of contexts in which the methods
and apparatus described herein should be useful will be provided.
Referring to FIG. 2, a Multiple Input Multiple Output (MIMO)
communication system 200 between an evolved Base Node (eNB) 202 and
User Equipment (UE) 204 utilizes a RACH procedure for an uplink 205
across a plurality of transmit (Tx) antennas 206a-206z. In
particular, a transmitter 208 of the UE 204 transmits uplink data
and other signals as described elsewhere herein from antennas
206a-206z in response to a computing platform 210 determining that
the RACH access response message provides an uplink grant
sufficient to empty the UE's data buffer. A receiver (Rx) 216 of
the UE 204 can receive a downlink 218 from the eNB 202, for
example, downlink portions of a RACH contention resolution
procedure and other data.
[0044] FIG. 3 illustrates a wireless communication system 300,
configured to support a number of users, in which the teachings
herein may be implemented. The system 300 provides communication
for multiple cells 302, such as, for example, macro cells
302a-302g, with each cell being serviced by a corresponding access
node 304 (e.g., access nodes 304a-304g). As shown in FIG. 3, access
terminals 306 (e.g., access terminals 306a-3061) may be dispersed
at various locations throughout the system over time. Each access
terminal 306 may communicate with one or more access nodes 304 on a
forward link ("FL") and/or a reverse link ("RL) at a given moment,
depending upon whether the access terminal 306 is active and
whether it is in soft handoff, for example. The wireless
communication system 300 may provide service over a large
geographic region. For example, macro cells 302a-302g may cover a
few blocks in a neighborhood.
[0045] In the example shown in FIG. 4, base stations 410a, 410b and
410c may be macro base stations for macro cells 402a, 402b and
402c, respectively. Base station 410x may be a pico base station
for a pico cell 402x communicating with terminal 420x. Base station
410y may be a femto base station for a femto cell 402y
communicating with terminal 420y. Although not shown in FIG. 4 for
simplicity, the macro cells may overlap at the edges. The pico and
femto cells may be located within the macro cells (as shown in FIG.
4) or may overlap with macro cells and/or other cells.
[0046] Wireless network 400 may also include relay stations, e.g.,
a relay station 410z that communicates with terminal 420z. A relay
station is a station that receives a transmission of data and/or
other information from an upstream station and sends a transmission
of the data and/or other information to a downstream station. The
upstream station may be a base station, another relay station, or a
terminal. The downstream station may be a terminal, another relay
station, or a base station. A relay station may also be a terminal
that relays transmissions for other terminals. A relay station may
transmit and/or receive low reuse preambles. For example, a relay
station may transmit a low reuse preamble in similar manner as a
pico base station and may receive low reuse preambles in similar
manner as a terminal.
[0047] A network controller 430 may couple to a set of base
stations and provide coordination and control for these base
stations. Network controller 430 may be a single network entity or
a collection of network entities. Network controller 430 may
communicate with base stations 410 via a backhaul. Backhaul network
communication 434 can facilitate point-to-point communication
between base stations 410a-410c employing such a distributed
architecture. Base stations 410a-410c may also communicate with one
another, e.g., directly or indirectly via wireless or wireline
backhaul.
[0048] Wireless network 400 may be a homogeneous network that
includes only macro base stations (not shown in FIG. 4). Wireless
network 400 may also be a heterogeneous network that includes base
stations of different types, e.g., macro base stations, pico base
stations, home base stations, relay stations, etc. These different
types of base stations may have different transmit power levels,
different coverage areas, and different impact on interference in
wireless network 400. For example, macro base stations may have a
high transmit power level (e.g., 20 Watts) whereas pico and femto
base stations may have a low transmit power level (e.g., 9 Watt).
The techniques described herein may be used for homogeneous and
heterogeneous networks.
[0049] Terminals 420 may be dispersed throughout wireless network
400, and each terminal may be stationary or mobile. A terminal may
also be referred to as an access terminal (AT), a mobile station
(MS), user equipment (UE), a subscriber unit, or a station. A
terminal may be a cellular phone, a personal digital assistant
(PDA), a wireless modem, a wireless communication device, a
handheld device, a laptop computer, a cordless phone, a wireless
local loop (WLL) station, etc. A terminal may communicate with a
base station via the downlink and uplink. The downlink (or forward
link) refers to the communication link from the base station to the
terminal, and the uplink (or reverse link) refers to the
communication link from the terminal to the base station.
[0050] A terminal may be able to communicate with macro base
stations, pico base stations, femto base stations, and/or other
types of base stations. In FIG. 4, a solid line with double arrows
indicates desired transmissions between a terminal and a serving
base station, which is a base station designated to serve the
terminal on the downlink and/or uplink. A dashed line with double
arrows indicates interfering transmissions between a terminal and a
base station. An interfering base station is a base station causing
interference to a terminal on the downlink and/or observing
interference from the terminal on the uplink.
[0051] Wireless network 400 may support synchronous or asynchronous
operation. For synchronous operation, the base stations may have
the same frame timing, and transmissions from different base
stations may be aligned in time. For asynchronous operation, the
base stations may have different frame timing, and transmissions
from different base stations may not be aligned in time.
Asynchronous operation may be more common for pico and femto base
stations, which may be deployed indoors and may not have access to
a synchronizing source such as a Global Positioning System
(GPS).
[0052] In one aspect, to improve system capacity, the coverage area
402a, 402b, or 402c corresponding to a respective base station
410a-410c can be partitioned into multiple smaller areas (e.g.,
areas 404a, 404b, and 404c). Each of the smaller areas 404a, 404b,
and 404c can be served by a respective base transceiver subsystem
(BTS, not shown). As used herein and generally in the art, the term
"sector" can refer to a BTS and/or its coverage area depending on
the context in which the term is used. In one example, sectors
404a, 404b, 404c in a cell 402a, 402b, 402c can be formed by groups
of antennas (not shown) at base station 410, where each group of
antennas is responsible for communication with terminals 420 in a
portion of the cell 402a, 402b, or 402c. For example, a base
station 410 serving cell 402a can have a first antenna group
corresponding to sector 404a, a second antenna group corresponding
to sector 404b, and a third antenna group corresponding to sector
404c. However, it should be appreciated that the various aspects
disclosed herein can be used in a system having sectorized and/or
unsectorized cells. Further, it should be appreciated that all
suitable wireless communication networks having any number of
sectorized and/or unsectorized cells are intended to fall within
the scope of the hereto appended claims. For simplicity, the term
"base station" as used herein can refer both to a station that
serves a sector as well as a station that serves a cell. It should
be appreciated that as used herein, a downlink sector in a disjoint
link scenario is a neighbor sector. While the following description
generally relates to a system in which each terminal communicates
with one serving access point for simplicity, it should be
appreciated that terminals can communicate with any number of
serving access points.
[0053] The teachings herein may be incorporated into a node (e.g.,
a device) employing various components for communicating with at
least one other node. FIG. 5 depicts several sample components that
may be employed to facilitate communication between nodes.
Specifically, FIG. 5 illustrates a wireless device 510 (e.g., an
access point) and a wireless device 550 (e.g., an access terminal
or UE) of a MIMO system 500. At the device 510, traffic data for a
number of data streams is provided from a data source 512 to a
transmit ("TX") data processor 514.
[0054] In some aspects, each data stream is transmitted over a
respective transmit antenna. The TX data processor 514 formats,
codes, and interleaves the traffic data for each data stream based
on a particular coding scheme selected for that data stream to
provide coded data.
[0055] The coded data for each data stream may be multiplexed with
pilot data using OFDM techniques. The pilot data is typically a
known data pattern that is processed in a known manner and may be
used at the receiver system to estimate the channel response. The
multiplexed pilot and coded data for each data stream is then
modulated (i.e., symbol mapped) based on a particular modulation
scheme (e.g., Binary Phase Shift Keying (BPSK), Quadrature Phase
Shift Keying (QSPK), M-ary Phase Shift Keying (M-PSK), or
Multi-Level Quadrature Amplitude Modulation (M-QAM)) selected for
that data stream to provide modulation symbols. The data rate,
coding, and modulation for each data stream may be determined by
instructions performed by a processor 530. A data memory 532 may
store program code, data, and other information used by the
processor 530 or other components of the device 510. For example,
the data memory 532 may store code and data used by the processor
530 to perform the base station side of an Uplink Data Arrival
(ULDAR) Random Access Channel (RACH) procedure, as disclosed
hereon.
[0056] The modulation symbols for all data streams are then
provided to a TX MIMO processor 520, which may further process the
modulation symbols (e.g., for Orthogonal Frequency-Division
Multiplexing (OFDM)). The TX MIMO processor 520 then provides NT
modulation symbol streams to NT transceivers ("XCVR") 522a through
522t that each has a transmitter (TMTR) and receiver (RCVR). In
some aspects, the TX MIMO processor 520 applies beam-forming
weights to the symbols of the data streams and to the antenna from
which the symbol is being transmitted.
[0057] Each transceiver 522a-522t receives and processes a
respective symbol stream to provide one or more analog signals, and
further conditions (e.g., amplifies, filters, and upconverts) the
analog signals to provide a modulated signal suitable for
transmission over the MIMO channel. NT modulated signals from
transceivers 522a through 522t are then transmitted from NT
antennas 524A through 524T, respectively.
[0058] At the device 550, the transmitted modulated signals are
received by NR antennas 552A through 552R and the received signal
from each antenna 552A-552R is provided to a respective transceiver
("XCVR") 554a through 554r. Each transceiver 554a-554r conditions
(e.g., filters, amplifies, and downconverts) a respective received
signal, digitizes the conditioned signal to provide samples, and
further processes the samples to provide a corresponding "received"
symbol stream.
[0059] A receive ("RX") data processor 560 then receives and
processes the NR received symbol streams from NR transceivers
554a-554r based on a particular receiver processing technique to
provide NT "detected" symbol streams. The RX data processor 560
then demodulates, deinterleaves, and decodes each detected symbol
stream to recover the traffic data for the data stream. The
processing by the RX data processor 560 is complementary to that
performed by the TX MIMO processor 520 and the TX data processor
514 at the device 510.
[0060] A processor 570 periodically determines which pre-coding
matrix to use. The processor 570 formulates a reverse link message
comprising a matrix index portion and a rank value portion. A data
memory 572 may store program code, data, and other information used
by the processor 570 or other components of the device 550. For
example, the data memory 572 may store code and data used by the
processor 570 to perform the user equipment side of an Uplink Data
Arrival (ULDAR) Random Access Channel (RACH) procedure, as
disclosed hereon.
[0061] The reverse link message may comprise various types of
information regarding the communication link and/or the received
data stream. The reverse link message is then processed by a TX
data processor 538, which also receives traffic data for a number
of data streams from a data source 536, modulated by a modulator
580, conditioned by the transceivers 554a through 554r, and
transmitted back to the device 810.
[0062] At the device 510, the modulated signals from the device 550
are received by the antennas 524A-524T, conditioned by the
transceivers 522a-522t, demodulated by a demodulator ("DEMOD") 540,
and processed by a RX data processor 542 to extract the reverse
link message transmitted by the device 550. The processor 530 then
determines which pre-coding matrix to use for determining the
beam-forming weights then processes the extracted message.
[0063] An ULDAR RACH procedure 600 in which, to pass contention
resolution the UE 602 must receive a Physical Downlink Control
Channel (PDCCH) message from the eNB (base station) 604 addressed
to the Cell Radio Network Temporary ID (C-RNTI) for the UE and
containing an uplink grant is illustrated by FIG. 6. Procedure 600
may not be optimal in circumstances where the amount of data in the
UE's uplink data buffer is small enough to be transmitted in an
uplink grant of a request for authorization. Nonetheless, the
procedure 600 may provide a comparison and context for more optimal
procedures and methods described herein.
[0064] The UE 602 may initiate the ULDAR RACH procedure 600 on
response to detecting data arrival 606 while the UE's uplink timing
is out of sync with the eNB 604, or while the system's scheduling
resource is not available. Such conditions are not uncommon in many
wireless communication systems. A RACH procedure may be initiated
608 by the UE 602 by transmitting a preamble message 608 to the
base station 604. The preamble message 608, also referred to herein
as "MSG1," may be characterized by being an efficient wireless
signal indicating that the UE 602 seeks to initiate a RACH
procedure for uplink of data, namely by requesting an uplink grant
from the base station 604. The preamble is designed to carry
minimal information so as to conserve system resources, and
therefore does not include any information about the data to be
uplinked by the UE. For example, the preamble does not indicate the
amount of data that the UE 602 needs to uplink to the eNB 604.
[0065] The eNB 604 responds to MSG1 by transmitting a RACH access
response 610, also referred to herein as "MSG2," to the UE 602. The
MSG2 610 includes an uplink grant to permit the UE 602 to transmit
metadata and other information to the eNB 604 to enable efficient
uplink of data from the UE 602 for use in the wireless
communications network. Advantageously, the uplink grant is
relatively small so that the base station does not over allocate
resources to UE's having a relatively small amount of data to
uplink. In some circumstances, the uplink grant may be a minimum
size; for example, large enough to transmit a request for
authorization to enable efficient uplink of data from the UE 602,
but no larger. In other circumstances, the uplink grant allocated
in MSG3 may be somewhat larger than minimum size, as determined by
the eNB in response to current conditions. For example, if the eNB
604 determines that it has excess capacity for receiving uplink
data, it may provide an uplink grant in MSG2 that is larger than
minimum size. However, in many circumstances the eNB 604 may not
make any determination of capacity or larger grant, instead simply
providing an uplink grant in MSG2 that is a predetermined size, for
example a minimum size.
[0066] The UE 602 may respond to the MSG2 access response by
transmitting a request for authorization for a scheduled
transmission 612, also referred to herein as a "MSG3," to the eNB
604. The UE may include metadata and other information in a MSG3
response 612 to the eNB 604 to enable efficient scheduled uplink of
data from the UE 602 for use in the wireless communications
network. For example, the UE 602 may transmit its C-RNTI, an
indication of a non-zero amount of data in its uplink data buffer,
such as a buffer status report (BSR), and MAC package data units
(PDUs), in the MSG3 request for authorization.
[0067] In response to the MSG3 request for authorization, the eNB
604 may generate and transmit a contention resolution response 614
using the PDCCH addressed to the C-RNTI for the UE 602. The
contention resolution response 614 may also be referred to herein
as a "MSG4." The MSG4 response 614 includes an uplink grant to the
UE 602 of a size large enough for the UE to uplink an amount of
data equal to or greater than the amount of data indicated in the
MSG3 BSR. In response to the MSG4 grant 614, the UE 602 uplinks 616
the data in its uplink data buffer to the eNB 604, as indicated by
the uplink grant. Thus, the ULDAR RACH provides for efficient
uplink when the amount of data to be uplinked exceeds the size of
the uplink grant provided by MSG2 610.
[0068] However, it is not uncommon for UE to have only a small
amount of data to uplink, that is, an amount small enough to
utilize the uplink grant provided by MSG2 in the RACH procedure
600. Under such conditions, a modified ULDAR RACH procedure 700 may
be used, as diagramed by FIG. 7. The procedure 700 maybe performed
using a UE 702 and eNB (base station) 704, which may be similar to,
or the same as, the UE 602 and eNB 604 used for procedure 600,
except for being equipped using suitable software or firmware to
perform the operations required for procedure 700. The initial
determination 706 or procedure 700 may be the same as the
determination 606 described for procedure 600. Likewise, the MSG1
preamble 708 of procedure 700 may be similar or identical to the
MSG1 preamble 608 of procedure 600, while the MSG2 access response
710 may be similar or identical to the MSG2 access response
610.
[0069] The MSG3 request for authorization for scheduled
transmission 712 in procedure 700, however, differs from its
counterpart in procedure 600. The UE 702 may generate and transmit
the MSG3 request 712 in response to determining that the amount of
data in the UE's uplink data buffer is small enough to utilize the
uplink grant provided by MSG2 710. For example, the UE 702 may
transmit its C-RNTI, an indication of zero data in its uplink data
buffer, such as a buffer status report (BSR) indicating zero, MAC
package data units (PDUs), and the data from the UE's uplink data
buffer in the MSG3 request for authorization 712.
[0070] From the BSR zero indication, the eNB 704 recognizes the
presence of data in the request 712, and handles the data for
communication over the wireless communication network as indicated
by control data from the UE 702. In addition, the eNB 704
recognizes that the UE does not need an additional uplink grant.
Therefore, the eNB 704 may respond with a MSG4 contention
resolution message 714 that contains no uplink grant; for example,
a PDCCH message addressed to the C-RNTI indicated in MSG3 and
lacking any further uplink grant. The UE 702 may, in response to
the MSG4 714, terminate the ULDAR RACH procedure 700 without
requiring any further uplink grant from the eNB 704 to empty the
UE's uplink data buffer. Thus, procedure 700 provides for more
efficient uplink under the specified conditions, which are
recognized at the UE 702 at 706 and when responding to MSG2
710.
[0071] With reference to the forgoing figures and description, a
method 100 for performing an ULDAR RACH procedure to uplink data
may include steps and operations has been described above in
connection with FIG. 1. Certain details pertinent to method 100
have been clarified by the discussion in connection with FIGS. 6-7,
with procedure 700 in FIG. 7 pertaining to a procedure consistent
with method 100. Further consistent with the method 100, and as
further illustrated by FIG. 8, an apparatus 800 may function as
user equipment in a wireless communication system. The apparatus
800 may comprise an electronic component or module 802 for
receiving an access response to a RACH preamble message to acquire
an uplink grant from a node of a wireless communication system,
wherein the access response provides an uplink grant to the UE for
a request for authorization to transmit uplink data to the node.
The apparatus 800 further comprises a module 804 for transmitting
the request for authorization including the uplink data to the node
in response to determining that the access response message
provides an uplink grant sufficient to empty the UE's data buffer,
thereby enabling termination of the RACH procedure without
requiring any subsequent uplink grant from the node.
[0072] The apparatus 800 may optionally include a processor module
810 having at least one processor; in the case of the apparatus 800
configured as a communication network entity, rather than as a
general purpose microprocessor. The processor 810, in such case,
may be in operative communication with the modules 802-804 via a
bus 812 or similar communication coupling. The processor 810 may
effect initiation and scheduling of the processes or functions
performed by electrical components 802-804.
[0073] In related aspects, the apparatus 800 may include a
transceiver module 814. A stand alone receiver and/or stand alone
transmitter may be used in lieu of or in conjunction with the
transceiver 814. In further related aspects, the apparatus 800 may
optionally include a module for storing information, such as, for
example, a memory device/module 816. The computer readable medium
or the memory module 816 may be operatively coupled to the other
components of the apparatus 800 via the bus 812 or the like. The
memory module 816 may be adapted to store computer readable
instructions and data for performing the processes of the modules
802-804, and subcomponents thereof, or the processor 810, or the
methods disclosed herein, and other operations for wireless
communications. The memory module 816 may retain instructions for
executing functions associated with the modules 802-804. While
shown as being external to the memory 816, the modules 802-804 can
include at least portions within the memory 816.
[0074] In further related aspects, the memory 816 may optionally
include executable code for the processor module 810 and/or ones of
the modules 802-804 to cause the apparatus 800 to perform a method
that comprises the steps of: (a) receiving, at user equipment (UE)
implementing a wireless communication protocol, an access response
to a random access channel (RACH) procedure preamble message to
acquire an uplink grant from a node of a wireless communication
system, wherein the access response provides an uplink grant to the
UE for a request for authorization to transmit uplink data to the
node; and (b) transmitting the request for authorization including
the uplink data to the node in response to determining that the
access response message provides an uplink grant sufficient to
empty the UE's data buffer, thereby enabling termination of the
RACH procedure without requiring any subsequent uplink grant from
the node.
[0075] Further operations 900 that may be performed by a UE in
conjunction with performing the steps of method 100 are shown in
FIG. 9. In the MSG3 request for authorization, the UE may provide
an indication that the UE's data buffer is empty 902. The
indication may be provided 902 using a BSR signal. Furthermore, in
response to transmitting the MSG3 request for authorization
including uplink data, the UE may initialize a contention
resolution (CR) timer 904. The UE may use the CR timer to determine
whether contention resolution is successful within the
predetermined period allowed by the timer.
[0076] If and when the CR timer expires or "times out," the UE may
discard the T-RNTI 906 assigned for the ULDAR RACH by MSG3, in
response to the expiration of the timer. The UE therefore treats
timer expiration as indicating that the ULDAR RACH procedure has
not been successful. In such case, the UE may initiate the RACH
procedure for the original uplink data after waiting for a defined
backoff period 908. Conversely, if the UE receives a response from
the base station acknowledging receipt of the UE's MSG3, as
described in more detail below, the UE may regard the ULDAR RACH as
being successful. In those cases where the UE regards the ULDAR
RACH as successful, it does not reinitiate the RACH procedure
unless and until it detects the arrival of new uplink data.
[0077] Consistent with the further operations 900, and as further
illustrated by FIG. 10, an apparatus 1000 may function as user
equipment in a wireless communication system. The apparatus 1000
may comprise an electronic component or module 1002 for providing
an indication that the UE's data buffer is empty in the request for
authorization (MSG3). The indication may be provided using the BSR
to indicate that the buffer is empty, or zero. The apparatus 1000
may comprise an electronic component or module 1004 for
initializing a contention resolution timer in response to
transmitting the request for authorization to the base station. The
apparatus 1000 may comprise an electronic component or module 1006
for discarding a temporary C-RNTI assigned to he UE in the request
for authorization, in response to expiration of the contention
resolution timer. The apparatus 1000 may comprise an electronic
component or module 1008 for reinitiating an ULDAR RACH procedure
at MSG1 for uplink of data from the UE, after waiting for a backoff
period.
[0078] The apparatus 1000 may optionally include a processor module
1010 having at least one processor; in the case of the apparatus
1000 configured as a communication network entity, rather than as a
general purpose microprocessor. The processor 1010, in such case,
may be in operative communication with the modules 1002-1008 via a
bus 1012 or similar communication coupling. The processor 1010 may
effect initiation and scheduling of the processes or functions
performed by electrical components 1002-1008.
[0079] In related aspects, the apparatus 1000 may include a
transceiver module 1014. A stand alone receiver and/or stand alone
transmitter may be used in lieu of or in conjunction with the
transceiver 1014. In further related aspects, the apparatus 1000
may optionally include a module for storing information, such as,
for example, a memory device/module 1016. The computer readable
medium or the memory module 1016 may be operatively coupled to the
other components of the apparatus 1000 via the bus 1012 or the
like. The memory module 1016 may be adapted to store computer
readable instructions and data for performing the functions of the
modules 1002-1008, and subcomponents thereof, or the processor
1010, or the methods disclosed herein, and other operations for
wireless communications. The memory module 1016 may retain
instructions for executing functions associated with the modules
1002-1008. While shown as being external to the memory 1016, the
modules 1002-1008 can include at least portions within the memory
1016. In further related aspects, the memory 1016 may optionally
include executable code for the processor module 1010 and/or ones
of the modules 1002-1008 to cause the apparatus 1000 to perform a
method that comprises any operable combination of the additional
operations 900 and method 100.
[0080] Further operations 1100 that may be performed by a UE in
conjunction with performing the steps of method 100 and/or the
additional operations 900 are shown in FIG. 11. The further
operations 1100 apply to embodiments wherein the UE includes 1102 a
C-RNTI MAC control element in the MSG3 request for authorization
with the uplink data. In addition, the UE may initialize a
contention resolution time as previously discussed in connection
with FIG. 9. In such embodiments, the UE may stop the CR timer and
discard the temporary C-RNTI 1104, in response to a PDCCH
transmission addressed to the C-RNTI received after transmission of
MSG3. The UE therefore uses receipt of the PDCCH transmission as an
indication that the ULDAR RACH has successfully completed uplink of
data from the UE.
[0081] Consistent with the further operations 1100, and as further
illustrated by FIG. 12, an apparatus 1200 may function as user
equipment in a wireless communication system. The apparatus 1200
may comprise an electronic component or module 1202 for including a
C-RNTI MAC control element in the request for authorization (MSG3)
transmitted from the EU to the base station. The apparatus 1200 may
comprise an electronic component or module 1204 for stopping the
contention resolution timer and discarding the temporary C-RNTI, in
response to receiving a PDCCH transmission addressed to the C-RNTI
after transmission of MSG3.
[0082] The apparatus 1200 may optionally include a processor module
1210 having at least one processor; in the case of the apparatus
1200 configured as a communication network entity, rather than as a
general purpose microprocessor. The processor 1210, in such case,
may be in operative communication with the modules 1202-1204 via a
bus 1212 or similar communication coupling. The processor 1210 may
effect initiation and scheduling of the processes or functions
performed by electrical components 1202-1204.
[0083] In related aspects, the apparatus 1200 may include a
transceiver module 1214. A stand alone receiver and/or stand alone
transmitter may be used in lieu of or in conjunction with the
transceiver 1214. In further related aspects, the apparatus 1200
may optionally include a module for storing information, such as,
for example, a memory device/module 1216. The computer readable
medium or the memory module 1216 may be operatively coupled to the
other components of the apparatus 1200 via the bus 1212 or the
like. The memory module 1216 may be adapted to store computer
readable instructions and data for effecting the processes and
behavior of the modules 1202-1204, and subcomponents thereof, or
the processor 1210, or the methods disclosed herein, and other
operations for wireless communications. The memory module 1216 may
retain instructions for executing functions associated with the
modules 1202-1204. While shown as being external to the memory
1216, the modules 1202-1204 can include at least portions within
the memory 1216. In further related aspects, the memory 1216 may
optionally include executable code for the processor module 1210
and/or ones of the modules 1202-1204 to cause the apparatus 1200 to
perform a method that comprises any operable combination of the
additional operations 1100, 900 and method 100.
[0084] Further operations 1300 that may be performed by a UE in
conjunction with performing the steps of method 100 and/or the
additional operations 900 are shown in FIG. 13. The further
operations 1300 apply to embodiments wherein the UE includes 1302 a
CCCH SDU in the MSG3 request for authorization with the uplink
data. In addition, the UE may initialize a contention resolution
time as previously discussed in connection with FIG. 9. In such
embodiments, the UE may stop the CR timer and discard a temporary
C-RNTI 1304, in response to determining that a UE contention
resolution ID decoded from a MAC PDU received from the base station
after transmission of MSG3 matches the CCCH SDU. The UE therefore
uses receipt of the MAC PDU as an indication that the ULDAR RACH
has successfully completed uplink of data from the UE.
[0085] Consistent with the further operations 1300, and as further
illustrated by FIG. 14, an apparatus 1400 may function as user
equipment in a wireless communication system. The apparatus 1400
may comprise an electronic component or module 1402 for including
CCCH SDU in the MSG3 request for authorization (MSG3) with the
uplink data transmitted from the EU to the base station. The
apparatus 1400 may comprise an electronic component or module 1404
for stopping stop the CR timer and discarding a temporary C-RNTI
1304, in response to determining that a UE contention resolution ID
decoded from a MAC PDU received from the base station after
transmission of MSG3 matches the CCCH SDU.
[0086] The apparatus 1400 may optionally include a processor module
1410 having at least one processor; in the case of the apparatus
1400 configured as a communication network entity, rather than as a
general purpose microprocessor. The processor 1410, in such case,
may be in operative communication with the modules 1402-1404 via a
bus 1412 or similar communication coupling. The processor 1410 may
effect initiation and scheduling of the processes or functions
performed by electrical components 1402-1404.
[0087] In related aspects, the apparatus 1400 may include a
transceiver module 1414. A stand alone receiver and/or stand alone
transmitter may be used in lieu of or in conjunction with the
transceiver 1414. In further related aspects, the apparatus 1400
may optionally include a module for storing information, such as,
for example, a memory device/module 1416. The computer readable
medium or the memory module 1416 may be operatively coupled to the
other components of the apparatus 1400 via the bus 1412 or the
like. The memory module 1416 may be adapted to store computer
readable instructions and data for effecting the processes and
behavior of the modules 1402-1404, and subcomponents thereof, or
the processor 1410, or the methods disclosed herein, and other
operations for wireless communications. The memory module 1416 may
retain instructions for executing functions associated with the
modules 1402-1404. While shown as being external to the memory
1416, the modules 1402-1404 can include at least portions within
the memory 1416. In further related aspects, the memory 1416 may
optionally include executable code for the processor module 1410
and/or ones of the modules 1402-1404 to cause the apparatus 1400 to
perform a method that comprises any operable combination of the
additional operations 1100, 900 and method 100.
[0088] Further details and relationships between actions that may
be performed by user equipment in different embodiments of an ULDAR
RACH procedure are summarized by the various blocks 1500 shown in
FIG. 15. Block 1502 refers to a sequence of RACH MSG1 transmission,
MSG2 receipt, and MSG3 transmission performed by the UE as
described hereinabove. Likewise, block 1504 refers to the UE
initializing a MAC contention resolution timer in response to
transmitting the MSG3 request with the uplink data. The UE may
restart the CR timer at each hybrid automatic repeat request (HARM)
retransmission. The UE may then, regardless of the possible
occurrence of a measurement gap, monitor the PDCCH until the CR
timer expires or until the UE stops the timer in response to
specified conditions.
[0089] At block 1506, a first branch point distinguishing different
cases or embodiments, concerns whether or not the UE subsequently
(after transmitting MSG3) receives a PDCCH transmission. If the
RACH is proceeding normally, the UE should receive a PDCCH
transmission in response to MSG3. If the UE does not receive a
PDCCH transmission and the MAC CR timer is not expired, the UE
continues to wait for the PDCCH transmission 1506. However, if the
MAC CR timer expires without the UE receiving a PDCCH transmission,
the UE discards the temporary C-RNTI and considers the contention
resolution/RACH procedure not successful 1522.
[0090] Referring again to block 1506, if the UE receives a PDCCH
transmission in response to MSG3, a second branch point 1508 turns
on whether or not the UE included a C-RNTI or a CCCH SDU in MSG3.
If the UE included a C-RNTI, then the PDCCH is addressed to the
included C-RNTI. In response to receiving this PDCCH transmission,
the UE may stop or reset the MAC CR timer and discard the temporary
C-RNTI 1510. The UE may then regard the contention resolution/RACH
procedure as having successfully completed uplink of the data
included in MSG3 from the UE 1512. This is true whether the RACH
was originally initiated by the MAC sublayer itself, resulting in
the MSG4 PDCCH transmission to the C-RNTI containing an UL grant
for a new transmission; or whether, in the alternative, the RACH
procedure was initiated by a PDCCH order and the MSG4 PDCCH order
addressed to the C-RNTI does not include a new UL grant.
[0091] In the alternative, if at 1508 the MSG3 transmission
includes a CCCH SDU, the UE determines 1514 whether the MAC PDUs in
the MSG4 received transmission can be successfully decoded. If the
MAC PDUs cannot be decoded, the MSG4 transmission is ignored and
flow reverts to block 1520. If the MAC PDUs can be decoded, the UE
checks whether the UE CR ID coded in the MAC PDUs matches the CCCH
SDU included in MSG3, at block 1516. If the UE CR ID matches the
CCCH SDU, then the UE may set the C-RNTI equal to the value of the
temporary C-RNTI, discard the temporary C-RNTI, and finish
disassembly and de-multiplexing of the MAC PDUs 1518. In addition,
the UE may then regard the contention resolution/RACH procedure as
having successfully completed uplink of the data included in MSG3
from the UE 1512.
[0092] Conversely, if the UE CR ID does not match the CCCH SDU, the
UE may discard the successfully decoded MAC PDU 1526, discard the
temporary C-RNTI, and regard the CR/RAC procedure as unsuccessful
1522. Regarding the CR/RACH procedure as unsuccessful means that
the UE will attempt to again uplink the data included in MSG3.
[0093] Accordingly, the UE may flush the HARQ buffer used for
transmission of the MAC PDU in the MSG3 buffer, and increment a
preamble transmission counter by one 1524. At block 1528, the UE
may determine whether the preamble transmission counter exceeds a
maximum value, e.g., "MAX+1." If the counter exceeds a
predetermined maximum value, the UE may indicate a RACH problem to
upper layers 1532. If the counter does not exceed the maximum
threshold value, the UE may as indicated at block 1530, based on a
predetermined backoff parameter in the UE, select a random backoff
time according to a uniform distribution between zero and the
backoff parameter, delay a subsequent RACH MSG1 transmission by the
backoff time and proceed to the selection of a RACH resource,
before reverting to block 1502.
[0094] It is noted that various aspects are described herein in
connection with user equipment. User equipment can also be referred
to as a system, a user device, a subscriber unit, subscriber
station, terminal, mobile device, mobile station, remote station,
remote terminal, access terminal, user terminal, user agent, or
access terminal. A user device can be a cellular telephone, a
cordless telephone, a Session Initiation Protocol (SIP) phone, a
wireless local loop (WLL) station, a PDA, a handheld device having
wireless connection capability, a module within a terminal, a card
that can be attached to or integrated within a host device (e.g., a
PCMCIA card) or other processing device connected to a wireless
modem.
[0095] Those of skill would further appreciate that the various
illustrative logical blocks, modules, circuits, and algorithm steps
described in connection with the aspects disclosed herein may be
implemented as electronic hardware, computer software, or
combinations of both. To clearly illustrate this interchangeability
of hardware and software, various illustrative components, blocks,
modules, circuits, and steps have been described above generally in
terms of their functionality. Whether such functionality is
implemented as hardware or software depends upon the particular
application and design constraints imposed on the overall system.
Skilled artisans may implement the described functionality in
varying ways for each particular application, but such
implementation decisions should not be interpreted as causing a
departure from the scope of the present disclosure.
[0096] As used in this application, the terms "component",
"module", "system", and the like are intended to refer to a
computer-related entity, either hardware, a combination of hardware
and software, software, or software in execution. For example, a
component may be, but is not limited to being, a process running on
a processor, a processor, an object, an executable, a thread of
execution, a program, and/or a computer. By way of illustration,
both an application running on a server and the server can be a
component. One or more components may reside within a process
and/or thread of execution and a component may be localized on one
computer and/or distributed between two or more computers.
[0097] The word "exemplary" is used herein to mean serving as an
example, instance, or illustration. Any aspect or design described
herein as "exemplary" is not necessarily to be construed as
preferred or advantageous over other aspects or designs.
[0098] Various aspects will be presented in terms of systems that
may include a number of components, modules, and the like. It is to
be understood and appreciated that the various systems may include
additional components, modules, etc. and/or may not include all of
the components, modules, etc. discussed in connection with the
figures. A combination of these approaches may also be used. The
various aspects disclosed herein can be performed on electrical
devices including devices that utilize touch screen display
technologies and/or mouse-and-keyboard type interfaces. Examples of
such devices include computers (desktop and mobile), smart phones,
personal digital assistants (PDAs), and other electronic devices
both wired and wireless.
[0099] In addition, the various illustrative logical blocks,
modules, and circuits described in connection with the aspects
disclosed herein may be implemented or performed with a general
purpose processor, a digital signal processor (DSP), an application
specific integrated circuit (ASIC), a field programmable gate array
(FPGA) or other programmable logic device, discrete gate or
transistor logic, discrete hardware components, or any combination
thereof designed to perform the functions described herein. A
general purpose processor may be a microprocessor, but in the
alternative, the processor may be any conventional processor,
controller, microcontroller, or state machine. A processor may also
be implemented as a combination of computing devices, e.g., a
combination of a DSP and a microprocessor, a plurality of
microprocessors, one or more microprocessors in conjunction with a
DSP core, or any other such configuration.
[0100] Furthermore, the one or more versions may be implemented as
a method, apparatus, or article of manufacture using standard
programming and/or engineering techniques to produce software,
firmware, hardware, or any combination thereof to control a
computer to implement the disclosed aspects. The term "article of
manufacture" (or alternatively, "computer program product") as used
herein is intended to encompass a computer program accessible from
any computer-readable device, carrier, or media. For example,
computer readable media can include but are not limited to magnetic
storage devices (e.g., hard disk, floppy disk, magnetic strips),
optical disks (e.g., compact disk (CD), digital versatile disk
(DVD)), smart cards, and flash memory devices (e.g., card, stick).
Additionally it should be appreciated that a carrier wave can be
employed to carry computer-readable electronic data such as those
used in transmitting and receiving electronic mail or in accessing
a network such as the Internet or a local area network (LAN). Of
course, those skilled in the art will recognize many modifications
may be made to this configuration without departing from the scope
of the disclosed aspects.
[0101] The steps of a method or algorithm described in connection
with the aspects disclosed herein may be embodied directly in
hardware, in a software module executed by a processor, or in a
combination of the two. A software module may reside in RAM memory,
flash memory, ROM memory, EPROM memory, EEPROM memory, registers,
hard disk, a removable disk, a CD-ROM, or any other form of storage
medium known in the art. An exemplary storage medium is coupled to
the processor such the processor can read information from, and
write information to, the storage medium. In the alternative, the
storage medium may be integral to the processor. The processor and
the storage medium may reside in an ASIC. The ASIC may reside in a
user terminal. In the alternative, the processor and the storage
medium may reside as discrete components in a user terminal.
[0102] The previous description of the disclosed aspects is
provided to enable any person skilled in the art to make or use the
present disclosure. Various modifications to these aspects will be
readily apparent to those skilled in the art, and the generic
principles defined herein may be applied to other embodiments
without departing from the spirit or scope of the disclosure. Thus,
the present disclosure is not intended to be limited to the
embodiments shown herein but is to be accorded the widest scope
consistent with the principles and novel features disclosed herein.
Advantageously, the technology as disclosed herein should be
accomplished within design guidelines for minimizing costs and
disruptions to existing network infrastructure, while ensuring
effective security. For example, implementations should be backward
compatible with existing mobile stations, as well as new devices.
The foregoing exemplary guidelines may be helpful in designing
useful embodiments, but do not limit the technology described
herein to a particular design constraint or set of constraints.
[0103] In view of the exemplary systems described supra,
methodologies that may be implemented in accordance with the
disclosed subject matter have been described with reference to
several flow diagrams. While for purposes of simplicity of
explanation, the methodologies are shown and described as a series
of blocks, it is to be understood and appreciated that the claimed
subject matter is not limited by the order of the blocks, as some
blocks may occur in different orders and/or concurrently with other
blocks from what is depicted and described herein. Moreover, not
all illustrated blocks may be required to implement the
methodologies described herein. Additionally, it should be further
appreciated that the methodologies disclosed herein are capable of
being stored on an article of manufacture to facilitate
transporting and transferring such methodologies to computers. The
term article of manufacture, as used herein, is intended to
encompass a computer program accessible from any computer-readable
device, carrier, or medium.
[0104] It should be appreciated that any patent, publication, or
other disclosure material, in whole or in part, that is said to be
incorporated by reference herein is incorporated herein only to the
extent that the incorporated material does not conflict with
existing definitions, statements, or other disclosure material set
forth in this disclosure. As such, and to the extent necessary, the
disclosure as explicitly set forth herein supersedes any
conflicting material incorporated herein by reference. Any
material, or portion thereof, that is said to be incorporated by
reference herein, but which conflicts with existing definitions,
statements, or other disclosure material set forth herein, will
only be incorporated to the extent that no conflict arises between
that incorporated material and the existing disclosure
material.
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